Screw Compressor Drive Energy Map via Stepwise Speed Profiling
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Solution Overview
Problem
Existing screw compressor systems driven by frequency converters face inefficiencies in determining optimal operation points, requiring lengthy test procedures and frequent recalibration due to changing system properties, which affects power consumption and efficiency.
Innovation Solution
A method involving a specific speed profile for pressurizing the pressure vessel, allowing internal measurements of the frequency converter to determine optimal rotation speeds without external instruments, generating an energy consumption map to minimize power usage based on pressure ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If excessive test procedures are conducted to gather consumption data in each operation point, then reliable operation point data can be obtained, but the time required increases significantly
Solution Approach 1:
The patent applies preliminary action by performing a single comprehensive filling test that captures operation point data for multiple operating conditions in advance. During this initial test, the screw compressor fills the pressure vessel while passing through various operation points, and the system records consumption data at each point. This preliminary data collection eliminates the need for separate excessive test procedures later, significantly reducing time while maintaining data reliability.
2Reliability
If frequent recalibration procedures are performed to account for changing system properties, then reliable efficiency determination can be maintained, but the complexity and time consumption increase
Solution Approach 1:
The patent implements feedback by continuously monitoring the pressure in the vessel during the filling process and using this information to identify which operation points are currently being traversed. The system compares real-time pressure data against stored operation point characteristics to automatically determine the current operating condition. This feedback mechanism allows the system to adapt to changing system properties dynamically during operation, maintaining reliability without requiring frequent external recalibration procedures.
3Measurement precision
If external measurement instruments are used to determine power consumption, then accurate efficiency data can be obtained, but the device complexity and measurement requirements increase
Solution Approach 1:
The patent applies self-service by utilizing the frequency converter's own internal measurement capabilities to determine power consumption and efficiency data. The frequency converter, which is already present in the system for speed control, contains built-in sensors and processing ability that can measure electrical parameters (voltage, current, power factor) and calculate power consumption. This eliminates the need for external measurement instruments such as separate power meters or measurement equipment, reducing device complexity while maintaining measurement accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the determination of optimal rotation speeds post-filling, reducing the need for frequent recalibration and external measurements, improving energy efficiency and operational stability by generating an energy consumption map for efficient operation.
Implementation Method 1
Frequency converters include typically processors having calculation capacity and internal measurements. The measurements relate, for example, to rotational speed, torque and power.
Data Source
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AI summary
A method of determining operation characteristics of a screw compressor drive and a screw compressor drive, the method comprising pressurising a pressure vessel of the screw compressor with a variable rotational speed of the screw compressor, the rotational speed of the screw compressor having a speed profile in which the rotational speed is changed stepwise such that between stepwise changes the rotational speed of the screw compressor is kept substantially constant for a time period, repeating the speed profile until the pressure of the pressure vessel reaches a set pressure value, determining pressure of the pressure vessel, power consumption of the screw compressor drive and mass flow rate during the pressurising when the rotational speed of the screw compressor is kept substantially constant, calculating energy efficiency of the screw compressor drive as a function of pressure of the pressure vessel and rotational speed of the screw compressor on the on the basis of the determined pressure of the pressure vessel and power consumption of the screw compressor drive.